Chirality-protected extreme asymmetric acoustic information transport with noise immunity

Chiral vortex beams with tunable topological charges (TCs) hold promise for high-capacity and multi-channel information transmission. However, asymmetric vortex transport, a crucial feature for enhancing robustness and security, often disrupts channel independence by altering TCs, causing signal distortion. Here, we exploit the radial mode degree of freedom in chiral space to achieve extremely asymmetric transmission with high energy contrast, while preserving chirality and TCs. This is enabled by radial mode modulation, induced by one-way momentum from an invasive metamaterial, resulting in full vortex transmission in one direction and complete isolation in the opposite. We further realize high-contrast asymmetric image transport by encoding information into different TC channels. Notably, this approach sustains near noise-immune performance at signal-to-noise ratios as low as -25 dB, owing to TC preservation and the orthogonality of vortices with differing TCs. Our findings present a new strategy for chiral beam control and pave the way for secure, directional, and noise-resilient information transport in structured wave platforms.